The present invention relates to a refrigerated display case capable of utilizing a unitary grid structure across the outlet air conduit openings without incurring any detrimental buildup of frost. The designation refrigerated display case is intended to refer both to cases maintained above 32.degree. F., such as dairy and fresh meat cases, and cases maintained below 32.degree. F., such as ice cream cases.
Typically in prior art refrigerated display cases, the outlet openings of the air conduits have been separately constructed with each having its own grid member over the opening. In the upright cases, i.e. those having front access openings, the outlet openings also have been staggered with the primary air conduit outlet opening being lower than the other outlet openings. Even with such formations, a problem that has typically occurred has been a buildup of frost across the outlet openings with such buildup being especially enhanced due to the temperature differential between the air emitted from the different openings. Such temperature differential causes the grid to drop below the dew point and results in an accumulation of condensation and a frost buildup.
In order to minimize such buildup of condensation, each outlet opening and the corresponding grid structure has been totally isolated from the openings and grids of the adjacent conduits. In addition, in order to minimize such condensation, electrical heater wires have been provided adjacent to the outlet openings, such as shown in U.S. Patent Application Ser. No. 876,748 to Fayez Abraham and Arthur Perez, filed Feb. 10, 1978; the subject matter of such application is hereby incorporated by reference.
Unitary grid structures have been utilized in open top refrigerated display cases such as disclosed in U.S. Pat. No. 4,106,305 to Fayez Ibrahim (now known as Fayez Abraham). While not commonly utilized or disclosed, U.S. Pat. No. 3,756,038 to MacMaster et al does disclose a common grid across the outlet openings of the primary and secondary air conduits of an open front display case.